Lubricating compositions containing highly basic metal sulfonates



Patented Feb. 12, 1952 UNITED STATE LUBRICATING COMP HIGHLY BASIC MOSITIONS CONTAINING ETAL SULI OBTAlIJES Paul R. Van E55 and Hulbert a.Sippie, Berkeley,

Calif., assignors-to Shell Development Company, San Francisco, Calii'.,a corporation of Delaware No Drawing. Application 3, 1943, Serial No.63,446

11 Claims.

This invention relates to compounded oleaginous compositions. Moreparticularly, it deals with'mineral lubricating oil compositionscontaining oil-soluble sulfonates. The invention also relates to newoil-soluble sulfonates which are particularly useful in the productionof compounded lubricating oils andother oleaginous compositions. It isalso concerned with new highly basic sulfonate salts and theirpreparation.

It is known that in modern internal combustion engines, including dieselengines and aviation engines, as well as ordinary automotive sparkignition engines, various products of combustion, fuel and/or oildegradation, condensation, polymerization, and the like, are generallyformed which result in piston ring sticking, valve sticking, andcorrosion of various metal parts of the combustion zone andauxiliary-parts functioning therewith. Accumulation of lacquer and/orcarbonaceous deposits on the rings and grooves and on valve stems andvalve guides ap pears to be the most probable reason for ring and valvesticking. The production of acidic bodies by the combustion of the fueland/or by the degradation of the lubricating oil as by partial oxidationand the like appears to be responsible, at least in part, for corrosionof engine parts associated with the combustion chamber and lubricated bymeans of the same lubricant utilized in the lubrication of the pistonrods, pistons, and the like. Also, acidic oxidation products accumulatedin lubricating oil appear to exert a catalytic effect in the oxidationof lubricating oil hydrocarbons.

The addition of various types of metal derivatives of organic compoundsto lubricating oils is known and practiced to minimize the difficultiesalready referred to and to improve the properties of these oils in otherrespects. Thus, various additives which exhibit detergent action inengines are used to minimize deposition of lacquers, resins.carbonaceous materials, and the like, on the engine parts. Basiccompounds, such as 'ba'sic'metal compounds, have been. used toprovide-"a base reserve to neutralize acidic compounds. Various metalcompounds which have been used for such purposes include the metalderivatives of such organic compounds as fatty acids, naphthenic acids,alcohols, phenols, ketones and the like, and corresponding basic orhydroxy salts thereof, instead of the neutral (normal) salt. wherein themetal is a polyvalent metal compound.

It is also known that calcium and other poly- 2 valent metal salts ofpetroleum or synthetic sulfonic acids have been used as engine oildetergent additio agents, and corresponding basic (hydroxy) s I, ts havebeen used additionally for their basici as neutralizing agent for acidicbodies in e lubricant, regardless of their source. As a source ofreserve alkalinity, the basic (hydroxy) polyvalent metal saltsheretofore available have been limited to the usual basic compounds.Thus, in the case of the basic calcium salts of hydrocarbyl sulfonicacids, the neutral salt of which is represented by the formula,(RSOaIaCa, the basic salt is represented by the formula, RSOa.Ca.QH,which is referred to as calcium hydroxy sulfonate. In general thematerial which has actually been available must be considered, based onanalysis, to be a mixture of neutral and basic salts since the freealkalinity of the material is less than the calculated value of thebasic salt, RSOa.Ca.0H.

It is an object of the present invention to provide a new class ofaddition agents for oils which are to be used as crankcase lubricantsfor internal combustion engines and which exhibit to a high degree thedesirable properties of inhibiting the development of corrosivity in theoil, of

improving oxidation stability of the oil, of promoting generalenginecleanliness, and reducing ring sticking, piston skirt varnishformation, and the like. Another object is to provide a more highlybasic sulfonate salt for use in various oleaginous compositions,including vegetable and animal oils, synthetic oils, mineral oils, etc.Still another object is to provide more highly basic sulfonate salts, ofboth the oil-soluble and water-soluble types, for various uses, and animproved method for their preparation. Other ob- Jects will appear fromthe description of the in-- vention.

It has now been found that improved oil compositions ,are obtained byadding to a lubricating 011 small amounts in the order of from about0.1% .to about 5% S. A. (sulfate ash), of an oil soluble complexpolyvalent metal hydroxy salt 3 salt. RSOe-M-(OH) although the lessbasic monohydroxy salt would be (RSOQMCOH). For polyvalent metals ingeneral the most basic simple hydroxy salt becomes RSO3'M(OH)D wherein bequals the valence of the metal M less one. This new complex may beprepared by treating the neutralor normal polyvalent metal sulfonate, inan inert, anhydrous, solvent medium therefor, with a polyvalent metalalcoholate of the same or a different metal, and subsequently treatingthe resultant product, from the interaction of the normal sulfonate andthe alcoholate, in a water-immiscible solvent for said resultantproduct, with water under conditions to hydrolyze the metal alcoholateand to produce in said water-immiscible solvent a mixed orcomplexoil-soluble polyvalent metal hydroxy sulfonate.

Various oil-soluble sulfonates may be utilized, including the salts ofthe well-known petroleum mahogany sulfonic acids, which are usuallyproduced. by the sulfonation of petroleum lubricating oil distillates,preferably rafllnates thereof, from selective solvent refining of thedistillate. with concentrated to fuming sulfuric acid, and whichmahogany acids remain in the 011 after settling out the acid sludge.These sulfonic acids may be represented by the formula R.SO:.H. whereinR. is usually a naphthenyl, alkylnaphthenyl, alkaryl or a naphthenylarylradical of a weight such that R.SOa.H generally has a molecular weightof from about 350 to about 500.

To prepare polyvalent metal, particularly alkaline earth metal, mahoganysulfonates, acidtreated oils or extracted (alcoholic) mahogany sulfonicacids may be neutralized directly with an oxide or hydroxide of thedesired metal and the mahogany sulfonates recovered. However, it isoften more convenient to recover the mahogany acids as the alkali metalsulfonate and then to convert them to the desired salt by doubledecomposition. Thus, the alkaline earth metal sulfonates may be made bytreating an alcoholic solution of sodium sulfonates with an alkalineearth metal salt. Or an oil solution of sodium sulfonate may beemulsified with an aqueous solution of the salt, to form an oil solutionof the alkaline earth metal sulfonate and an aqueous solution ofinorganic salts.

Instead of the petroleum mahogany acids, synthetic oil-soluble alkylatedaromatic sulfonic acids may be utilized in the preparation of theoil-soluble sulfonates of the invention.

other normal or neutral polyvalent metal sulfonates, such as those fromthe water-soluble green petroleum sulfonates, or simple basic saltsthereof. the lower alkanesulfonates (calcium methanesulfonate, magnesiumethanesulfonate, etc), and the like, may be similarly reacted withpolyvalent metal alcoholates, followed by hydrolysis, to produce highlybasic polyvalent metal sulfonates.

Although sulfonates of the alkaline earth metals, :1. e. calcium, bariumand strontium, and the closely related highly basic metal magnesium, arepreferred in the practice of the invention, oilsoluble sulfonates ofother polyvalent metals, such as zinc, almninum, cobalt, tin, are alsouseful.

The polyvalent metal alcoholates are preferably those of the alkalineearth metals, of magnesi and zinc and of aluminum, all of which arereadily prepared, as is well known, by interaction between the metal anda suitable alcohol, preferably an aliphatic alcohol of from about one tofour carbon atoms and which gives a water ethanol, normal andiso-propanol (preferably normal). and the butanols, preferably theprimary butanols. normal and iso-butanoL- Higher alcohols, bothaiicyclic and acyclic alcohols, may be utilized if a proper selection ofreaction condition is made to produce the alcoholate. and also theconditions for hydrolysis of the resulting sulfonate-alcoholatecombination are made more vigorous. such as by use of elevatedtemperatures, under superatmospheric pressure if required.

In accordance with the present invention, a polyvalent metal sulfonateand a polyvalent metal alcoholate are combined and reacted undersubstantially anhydrous or non-aqueous conditions for a substantialperiod of time and under conditions to effect the formation of a complexcompound. This can be advantageously effected in the case of theoil-soluble sulfonates by intimately contacting aldry (non-aqueous)solution of the sulfonate in a water-immiscible solvent medium thereforwith the alcoholate. Suitable waterimmiscible solvents are, for example,mineral oils of lubricating viscosity or some other mixture ofhydrocarbons, or an individual hydrocarbon, aromatic or non-aromatic,and mixtures thereof, or a suitable halogenated hydrocarbon. In the caseof solvents unsuitable as lubricants or components thereof, it ispreferred that they be sufllciently volatile to be readily removed fromthe product by distillation. Various alcohols alone may be used also asa solvent medium for the reaction. The alcoholate may advantageously bedissolved and/or suspended in a further portion of the alcohol fromwhich the alcoholate is made.

The reaction admixture may be warmed or heated if necessary. Followingthe interaction of the normal salt and the alcoholate, the water-solublesolvent present, such as alcohol, is removed, as by distillation.Thereafter, the resulting mixture can be filtered or centrifuged toseparate any undissolved material, and the homogeneous mixture ofaddition product dissolved in the water-immiscible solvent medium. or inany other such medium if the first is removed along with the watersoluble solvent, is intimately contacted with water or an aqueoussolution of a water-soluble salt of the polyvalent metal to hydrolyzethe alcoholate portion of the addition product. The hydrolysis isadvantageously carried out at a temperature near the boiling point ofthe solvent,

if that is below the boiling point of water, or with steam, which may ormay not be superheated, if the boiling point of the solvent is higherthan the temperature of the steam.

For water-soluble and oil-insoluble sulfonates other non-aqueous solventmedia may be used. although, under certain conditions, the use of suchsolvents may be eliminated. The alcohol corresponding to the alcoholateis usually a suitable solvent for such combinations.

For either type of sulfonate the lower molecular weight simple alcoholsmay be used as solvent media, and the alcoholate may be prepared andreacted with the sulfonate by contacting the alcohol-active metaldirectly with the alcohol solution of sulfonate. The alcoholate thusformed in situ reacts directly with the sulfonate. The hydrolysis may beeffected thereafter either in the presence or absence of the alcohol.

The exact nature of the product resulting from the interaction of thepolyvalent metal sulfonate and the polyvalent metal alcoholate, or ofthe product produced as a; result of the hydrolysis tment of thesulfcnate-alcoholate, are not known at present. It may be a colloidaldispersion ofwalcoh'olate in a mixed a-lcoholate-sulfonate, or

of metal hydroxide in basic metal sulfonate, re-' spectively. However,various physical methods applied to resolve the material were notsuccessful. On the other hand, there is evidence which indicates thatsome kind of complex compound formation is effected. The resulting oilsolution of'the basic material exhibits characteristics of homogeneity,there bing substantially no separation when filtered through biologicalfilters-or when subjected to centrifugation under a force of 10,000 g.The complex basic compound has a free alkalinity or basicity insubstantial excess over that of the simple basic salt and may berepresented, in general, by the formula (RSOZi)aM(OH)b.M'(OH)m or theequivalent empirical formula (RSOaiaMMKOHMM wherein R is an organic,preferably hydrocarbyl, radical, the sum of "a and b is the valence ofthe polyvalent metal M,-and n is the valence of the polyvalent metal M,both M and M 'preferably being divalent metals of the alkaline earthmetal group and magnesium, which metals together may be termed thestrongly basic metals of group II of the periodic classification. Fordivalent metals the foregoing empirical formula is simplified toRSOa.M=(OH) 1 wherein it is clear that y+1=2x and that the ratio oftheequiv?" alents of hydroxyl and metal, that is the ratio of 1! to :c(y/x), is greater than 1 (1 is the ratio for the simple basic compoundRSO3.M.OH) and less than 2 (2 would be the ratio in the divalent metalhydroxide M(OH)2). It will be seen from this that 11/21: is the ratio'ofthe number of valences of the metal which are bound to hydroxide groupsto the total number of valences (equivalent weights) of the metalpresent, and that this ratio thus represents the fraction of the metalpresent that is accountable for as titratable basicity. The ratio of yto a: (y/x), therefore, is numerically exactly twice the fraction of themetal which is accountable for as titratable basicity.

iwithout intending to be bound by any, hypothesis or theory concerningthe basic sulfonates of the invention, at least some of the results ofanalyses may be interpreted to indicate the presence therein of complexcompounds of the type represented by'the following formula, taking basicmagnesium petroleum sulfonate as-illustrative:

RSO2.OMgOH.Mg(OH)a The Mg(OH)2 quite possibly and probably is bound tothe RSOaOMgOH by means of secondary valence forces linking the Mgatom tothe accusecounted for by one or more combinationsof the followingreactions:

I (R.S0;.0);Mg Mg(OR');-2R.SO;.OMOR' Sulfonste Alcoholate Mixedsulionatealooholete Mixed sulfonate- Alcoholate Com lex compound ofmixed alcohoiate su onate-alcoholate and of alcoholate m 11.50;.0Mg.OR.Mg(OR')| anon-asm monmuon Variations in the free alkalinity ofthe product are attributable to various proportions of differentsubstances having different basicities, as will be readily understood,the-mixtures being representable by the empirical formula RSOa.Mg=. (OH)11 Example I Thirty-eight and one-half pounds (0.053 mol) of oil-solublesodium petronate (Sonnebom 715 base,sulfated residue=9.83%) wasdissolved in 15 gallons of benzene in a 25 gallon iron agitator providedwith a pressure steam jacket and an air-driven stirrer. To this solutionwas added 6.1 pounds (0.06 eq., a 10% excess) of magnesium chloridehexahydrate (MgClafiHzQ) dissolved in 2.5 gallons of water. The reactionwas heated. with stirring, at C. for 3 hours, then allowed to settleovernight-about 16 hours. After removal of the stratified aqueous phase,the benzene solution was washed twice with 2.5 gallon portions ofaqueous-10% MgClafiHzO and twice with water. Benzene was added from timeto time to maintain the total volume at 15 gallons. The dissolved waterwas removed by an azeotropic distillation, adding make-up benzene asrequired.

Magnesium methylate was prepared by reacting 1.3 pounds (0.053pound-atom) of magnesium tumings in one quart of methanol in a 22 literflask provided with an air-stirrer and condenser.

The vigorous reaction that ensued upon mixing the reactants wascontrolled by an ice bath. Ad-

ditional methanol 'was added until a total of three gallons had beenintroduced. Toward the end of the reaction, heat was applied to ensurecomplete reaction and to dissolve as much magnesium methylate aspossible in the methanol.

The dispersion (suspension and solution) of magnesium methylate (0.053mol) in 3 gallons of methanol was added to the anhydrous benzenesolution of normal magnesium petronate (petroleum sulfonate, 0.053eq.=0.0265 mol) in a 50 gallon Pfaudler kettle and the reaction mixturewas stirred 'at 45 C. for 1 hour. The methanol was then removed bydistillation as an azeotrope accuses The 15 gallons of filtered benzenesolution was water-treated batch-wise. Two liters of filtered benzenesolution was diluted further with 2 liters of benzene. The solution,heated to near boiling. was placed in a 10 liter separatory funnelwherein it was water-treated. The water treatment was accomplished byadding 800 ml. of warm, aqueous 10% MgClz6HzO and gently swirling thefunnel- The aqueous phase quickly settled and was drawn ed; a secondsimilar wash was given. The separated benzene layer was subjected todistillation to remove residual water azeotropically, adding benzene asrequired After removal of water, benzene was distilled oil, the lasttrace under reduced pressure (1 hr. at mm. Hg)

There was thus obtained from the 15 gallons, 25 pounds of a dark brown,Viscous material which was a highly basic magnesium petronate.

having the following properties:

Sulfated residue (770 C.) 26.4% by wt. Base neutralization No.(electrometric) 202 mg. KOH/g. Sodium content (expressed as NazSOr)1.76% by wt. Per cent basicity 1 83% (Empirical formula,RSO:.Mg2.04(OH)c.aa)

Percentage of total metal accountable as titratable basicity.

The foregoing described highly basic magnesium petronate forms an oilsolution in mineral lubricating oil which is relatively stable todrastic hydrolysis conditions in the presence of C02 and water, thedepletion, as measured by loss in basicity, being only 10% as comparedwith 22% for a commercially available good grade of an oil-soluble basiccalcium petronate. The material exhibits marked oxidation stability andconsiderable oxidation inhibition characteristics. A blend of thematerial in a highly refined lubricating mineral oil, in proportions togive a sulfated residue of 1.77%, gave a Dornte time (1500 cc. of oxygenabsorption in presence of a crankcase catalyst) of 57 hours and a TBCand 0 time (1500 cc. oxygen) of 106 hours, indicating improved oxidationstability, with a copper-lead bearing weight loss of only 2.1 mg./cm.The corresponding Dornte and TBC and 0 times in the same oil, and evenat a slightly higher concentration (S. A.=2.0%) for a commerciallyavailable good grade of an oilsoluble basic calcium petronate are hoursand 6.6 hours, respectively, while those for neutral calcium petronateare 7 hours and 1 hour, respec tively.

Example I! (an acid (H2804) treated. caustic soda neural-- ized,clay=treated rate from a selective solvent refined neutral distillatecut from a Poso- Coalinga crude mixture) having an SSU viscosity ofabout 620 at 100 F. and a viscosity index of 54. The oil solution wasintimately contacted with 61 grams of MgClz.6H2O dissolved in 500 cc. ofwater for 2 hours at 00 C. The aqueous and oil phases were allowed tostratify and then separated. The separated oil phase was washed twicewith 200 cc. portions of warm 10% MgClz.6l-Iz0 and layered oil. The oilphase was then heated to 150 (3., with stirring, to drive ofi excesswater. The resulting oil solution of e neutral agnesium 'petronatecontained only 0.011% sodium.

Five-tenths (0.5) or a gram-atom of magnesium was reacted with 500 cc.of methanol in the usual manner (see Example I) and the resultingmethanol dispersion 0! magnesium methylate was added to the oil solutionof neutral magnesium petronate, and the mixture stirred for 2 hours at60 C. The temperature was then raised to C. ior one-halt hour and thento C. for 15 minutes to remove traces oi methanol. To the methanol-treeoil solution of the resulting petronate-alcoholate was added 22 cc. (1.2mols) of water and the intimately contacted mixture was cooked at 95 C.for 1 hour. The excess waterwas removed by heating for 2 hours at 120 C.and then at C. for 20 minutes. Foaming had ceased at the end or the2-hour heating period at 120 C. If desired antifoaming agents such asalkyl silicones and silicates may be used advantageously to reduce thefoaming. The resulting oil solution was diluted with an equal volume ofthe same highly refined mineral oil and filtered while hot successivelythrough canvas and No. 4 filter paper; no residue was separated oneither filter material. The resulting oil solution was slightly cloudyin appearance but various tests indicated the homogeneity of the productadditive therein. The following results were obtained upon analysis:

Basicity 36.2 mg. KOH/g. Sulfated ash or residue S. A.) 5.03 Per centbasicity 1 77.0%

(Empirical formula. RSOaJMgmflOHhsc) Example nu An oil concentrate 01 ahighly basic oil-soluble calcium petronate (petroleum sulfonate) waspre- .pared by the same method as used in Example 1',

except that calcium chloride was used in place of "magnesium chloride inthe preparation of the neutral petronate and calcium and ethanol wereused in place of magnesium and methanol for the metal alcoholatepreparation and subsequent interactions thereof. Oil solutions or theresulting highly basic calci petronate were also conslderably mproved incharacteristics over oil so-- lutions oi both the commercial basiccalcium petronate and neutral calcium petronate. The product had abasicity of 84.6 mg. KOH/gram; a sulfated ash of 19.3%, and a per centbasicity, as already defined. of 52%. thus an empirical forsouls ofRsO3-C84l.04(OH)1.08. Thus, this product had a per cent basicity inexcess of that of the theoretical monohydroxy (monobasic) calciumpetroleum sulionate (RSOa.Ca.OH) theoretical value of which is 50%Example IV calci sulionate, having a basicity of 11 mg.

KQlHl/g. material, a suliated ash value of 5%. a

27% metal present as titratable base (empirical formula (RS031.46C&.(OH)0.54) was converted into a more highly basic product bydilution with benzene and treating with an ethyl alcohol solution ofcalcium ethylate, removing the benzene and alcohol, followed byhydrolysis and then drying of the oil product, following the techniquesalready discussed in the preceding examples. The resulting oilconcentrate had a basicity of 39.6 mg. KOH per gram of material and asulfated ash value of 8.0%; hence, 60% metal accountable as basicity(empirical formula RSOs.Cai.2s.(OH) 1.5.)

This new productwas characterized by its ability to impart much improvedproperties to lubricating oil compositions as compared with the basicpetroleum sulfonate from which it was prepared.

When the oil-soluble highly basic polyvalent metal sulfonates of theinvention are used in olea'ginous compositions of lubricating viscositythe proportion generally ranges from about 0.1% by weight, expressed assulfated residue,'up to saturation, but it is preferred to use fromabout 0.3%

to about 2.0%.

It will be understood that the basic sulfonates of this invention may beused in lubricating and other oil compositions together with any of thewell known compatible additives used to impart oxidation stability, toimpart extreme pressure properties, and the like.

The oil-soluble highly basic sulfonates of this invention are alsouseful in oleaginous compositions other than those which are intendedfor use as lubricating compositions, as well as in other non-aqueouscompositions. Thus, they are valuable as additives for fuelcompositions, and other light hydrocarbon compositions, such as rustpreventive hydrocarbon compositions, and the like. On account of theirsurface-active properties, they are also useful in the preparation ofoil and water emulsions. They are also useful in spray oils, and thelike.

The water-soluble highly basic sulfonates are also useful in thepreparation of various oil and water emulsions, such as oil-water spraycompositions and the like. They are also useful components ofmetal-cleaning compositions of a hydrophilic character, particularlythose which contain oxygenated organic compounds, such as alcohols,alcohol-ethers, etc.

Thus, the present invention provides a new polyvalent metal basicsulfonate with an alkalinity or basicity at least greater than thetheoreti- 'cal value of the corresponding simple basic sulfonate; itprovides a new and improved method for the production of basicsulfonates and it provides improved oleaginous compositions containingoil-soluble highly basic sulfonates.

We claim as our invention:

, l. A method for the preparation of an oil-soluble highly basicmagnesium petroleum sulfonate which comprises intimately contactingabout one mol proportion of an oil-soluble neutral magnesium petroleumsulfonate dissolved in a waterimmiscible organic solvent therefor whichis nonreactive with polyvalent metal alcoholates with about two molproportions of a water-reactive magnesium alcoholate of a lowermolecular weight monohydric simple alcohol of 1 to 4 carbon atoms undersubstantially non-aqueous conditions, subsequently treating the solventsolution of the resulting product with water to hydrolyze the alcoholateto an hydroxide, and separating the solvent and resulting oil-solublebasic magnesium aeeacao of a water reactive divalent metal alcoholateun- 7 l0 petroleum sulfonate dissolved therein from residual water. Y

2. A method for the preparation of an oil-soluble highly basic divalentmetal organic sulfonate which comprises intimately contacting about oneequivalent weight of an oil-soluble organic sulfonate of a metalselected from the strongly basic metals of group II of the periodictable dissolved in a water-immiscible solvent therefor which isnon-reactive with divalent metal alcoholates with at least about twoequivalent weights der substantially anhydrous conditions to produce acomplex of the sulfonate and alcoholate. treating the resulting solutionwith water to hydrolyze the alcoholate to an hydroxide, and separatingthe solvent and dissolved basic sulfonate material from unreacted water.

3. A method for'the preparation of a mineral lubricating oil compositionwhich comprises dispersing about one equivalent weight of an oilsolublepetroleum sulfonate of a metal selected from the strongly basic metalsof group II of the periodic table in a refined mineral oil oflubricating viscosity, intimately contacting the resulting dispersionunder substantially anhydrous conditions with a dispersion of at leastabout two equivalent weights of a water-reactive polyvalent vmetalalcoholate ina portion of the corresponding alcohol, said alcohol beinga lower molecular weight simple aliphatic alcohol of 1 to 4 carbonatoms, treating the oil solution of the resulting product with water tohydrolyze the alcoholate to hydroxide, removing excess water and anyalcohol from the resulting oil solution and thereby recovering a minerallubricating oil composition containing an oil-soluble basic polyvalentmetal sulfonate. i

a. A method for the preparation of an oilsoluble highly basic alkalineearth metal petroleum sulfonate which comprises intimately contactingone mol proportion of an oil-soluble neutral alkaline earth metalpetroleum sulfonate dissolved in a water-immiscible organic solventtherefor which is non-reactive with polyvalent metal alcoholates withabout two mol proportions oi a water-reactive alkaline earth metalalcoholate of a lower molecular weight monohydric simple alcohol undersubstantially nonaqueous conditions to produce a complex of thesulfonate and alcoholate, subsequently treating the solvent solution ofthe resulting product with water sumcient to hydrolyze all of thealcoholate to hydroxide and form free alcohol, and separating thesolvent and resulting oil-soluble basic alkaline earth metal petroleumsulfonate in which more than 50% of the alkaline earth metal present isaccountable as titratable basicity from residual water and free alcohol.

5. A mineral lubricating oil composition prepared by the method of claim3. r

6. A mineral lubricating oil composition prepared by the method of claim3 and wherein the metal of the oil-soluble petroleum sulfonate and ofthe metal alcoholate is calcium.

'I. A mineral lubricating oil composition prepared by the method ofclaim 3 and wherein the metal of the oil-soluble petroleum sulfonate andof the metal alcoholate is magnesium.

8. A mineral lubricating oil comprising a major proportion of a minerallubricating oil and a minor portion, of an oil-soluble highly basicdivalent metal petroleum sulfonate of a strongly basic metal of group IIof the periodic table. which a free basicity substantially greater ill vthan that of the correspon :t monobasic divalent metal petroleumsulionate (.MDH- wherein M is the divalent metal andREO: is petroleumsulfonate) the highly hasic petroleum sulfonate being prepared byintimately contacting about one mol proportion of an oil-solublepetroleum sulfonate of a strongly basic metal of group H oi the periodictable dissolved in a water-= immiscible organic solvent therefor, whichis nonreactive with divalent metal alcohoiates, with at least about twomol proportions of en alcoholate of a strongly basic divalent metal ofgroup II of the period table and viewer moieculcr weight monohydricsimple alcohol crime 4 carbon a under substantially non-aqueousconditions, subsequently treating the solvent solution oi the re--sulting product with water to hydrolyze the alcoholate to an hydroxideand recovering the resulting oil-soluble highly basic .divaient metalpetroleum sulfonate from residual water and alcohol. 9. A lubricatingcomposition according to claim 8, wherein the highly basic petroleumsulronate is a magnesium petroleum sulfonate which has the baslcity 0!.a substance represented by the formula RSOa.Mg2(OH) 3.

10. A lubricating composition according to sesame l2 3, wherein thehighly basic petroleum sulionai'e has the basicity of a basic divalentmetal 4 nnrnnnncns omen The following references are of record in thefile of this patent:

UNITED STATES PATENTS Number Name Date 2,361,804 Wilson Oct. 31,19442,402,325 Griesinger June 18, 1940 2,413,311 Cohen Dec. 31. 19462,444,970 Zimmer July 13; 1948 2,467,176 Zimmer Apr. 12, 1949 2,485,861Campbell Oct. 25, 1949 2,501,732 Mertes Mar. 28. 1950

8. A MINERAL LUBRICATING OIL COMPRISING A MAJOR PROPORTION OF A MINERALLUBRICATING OIL AND A MINOR PORTION OF AN OIL-SOLUBLE HIGHLY BASICDIVALENT METAL PETROLEUM SULFONATE OF A STRONGLY BASIC METAL OF GROUP IIOF THE PERIODIC TABLE, WHICH A FREE BASICITY SUBSTANTIALLY GREATER THANTHAT OF THE CORRESPONDING MONOBASIC DIVALENT METAL PETROLEUM SULFONATE(RSO3M.OHWHEREIN M IS THE DIVALENT METAL AND RSO3 IS PETROLEUMSULFONATE), THE HIGHLY BASIC PETROLEUM SULFONATE BEING PREPARED BYINTIMATELY CONTACTING ABOUT ONE MOL PROPORTION OF AN OIL-SOLUBLEPETROLEUM SULFONATE OF A STRONGLY BASIC METAL OF GROUP II OF THEPERIODIC TABLE DISSOLVED IN A WATERIMMISCIBLE ORGANIC SOLVENT THEREFOR,WHICH IS NONREACTIVE WITH DIVALENT METAL ALCHOLATES, WITH AT LEAST ABOUTTWO MOL PROPORTIONS OF AN ALCOHOLATE OF A STRONGLY BASIC DIVALENT METALOF GROUP II OF THE PERIODIC TABLE AND A LOWER MOLECULAR WEIGHTMENOHYDRIC SIMPLE ALCOHOL OF 1 TO 4 CARBON ATOMS UNDER SUBSTANTIALLYNON-AQUEOUS CONDITIONS, SUBSEQUENTLY TREATING THE SOLVENT SOLUTION OFTHE RESULTING PRODUCT WITH WATER TO HYDROLYZE THE ALCOHOLATE TO ANHYDROXIDE AND RECOVERING THE RESULTING OIL-SOLUBLE HIGHLY BASIC DIVALENTMETAL PETROLEUM SULFONATE FROM RESIDUAL WATER AND ALCOHOL.